Pulsation dampener



Patented Jan. 22, 1952 PULSATION DAMPENER Douglas Ragland, Houston, Tex., assignor, by

mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application October 28, 1946, Serial No. 706,198

3 Claims. 1

The present invention is directed to a device for dampening or suppressing the pulsations in a liquid stream. The device is particularly adapted to suppressing or dampening the pulsations in the outlet line of a reciprocating pump.

It is well known to the art that the liquid stream in the outlet line of a reciprocating pump has a cyclic variation in pressure. That is to say, during each stroke of the pump the pressure rises as the piston forces the liquid through the outlet port and then diminishes on the return stroke as the cylinder is again filled with liquid from the inlet port. In many installations of reciprocating pumps the pulsations in the outlet line are not particularly disadvantageous; however, in some installations it is desirable that such pulsations in the liquid stream be suppressed or dampened. For example, in compounding reciprocating I pumps it is necessary or desirable to suppress or dampen the vibration in the fluid stream forced from the outlet port of a reciprocating pump to the inlet port of a second in order to prevent exdevise a device suitable for installation in theoutlet line of a reciprocating pump which will suppress or eliminate periodic pressure changes in the outlet stream of the pump.

It is a further object of the present invention to devise a means which may be arranged in the line connecting the outlet port of a reciprocating pump to the inlet port of another reciprocating pump for dampening or "suppressing the periodic vibrations in the liquid being fed from one pump to the other pump.

The device of the present invention may be described briefly as involving a metallic case capable of resisting deformation at the pressure to which it is subjected and serving as an exterior element, an elastic member with edges sealed to the external case thereby forming a fluid-tight cavity between a surface of the flexible member and the inner surface of the external case, means arranged for filling the cavity with a compresby-the following description taken with the drawing in which the sole figure is in the form of an elevation, partly in section, illustrating an embodiment of the present invention.

2 Turning now specifically to the drawing, a cylindrical member or case ll provided with screw threads i2 and I3 on the exterior end surfaces thereof forms the outer casing of the device. An inner cylindrical member or mandrel I4 is provided with a plurality of perforations IS in the center portion thereof and one end is provided with external screw threads vl6. The screw threads I'6 are arranged so that the member may readily be attached to a pipe or line carrying a fluid stream; such a line is not shown in the drawing but it will be understood that it may be a conventional pipe connected, for example, from the outlet of a reciprocating pump to the inlet of another riciprocating pump to allow compounding of the reciprocating pumps. I

Mounted between outer case I l and inner perforated mandrel M is a flexible member ll. For convenience this member is hereinafter termed a rubber sleeve, although it will be understood that it may be constructed of any suitable material having the required elasticity and flexibility. A valve I9 is mounted in case I l to allow the chamber l8 defined between the outer surface of rubber sleeve l1 and the inner surface of case ii to be filled with a compressible fiuid, such as compressed air.

Rubber sleeve H has its ends mounted to make a fluid-tight seal with cylinder ll. Means sealing the ends of rubber sleeve 11 include end plates 20 and 2|. End plate 20 is in the form of an annulus and has its inner circumference firmly fixed in a fluid-tight manner, as by welding, to mandrel l4. End plate 2| is circular in shape. It will be seen that surfaces of end plates 20 and 2| are adapted to abut the ends of case ll. Cap 22 is attached to case H by screw threads and maintains case II in contact with end plate 20. End plate 2| is not firmly fixed to mandrel I4 but is retained in position in contact with casing H by means of cap 23 which is attached by screw threads to casing l I. Rubber sleeve I1 is of such a configuration that the major portion thereof is in the form of a cylinder with parallel sides while its ends are thickened and tapered to define wedge-shaped surfaces. A support ring 25 is embedded in each end of the sleeve. Each support ring is provided with bolts 25a which provide means for drawing the ends of the sleeve against end plates 20 and 2|, respectively.

Secured to end plate 20 by a suitable means, as by welding, is an inner member 26 defining a cylindrical inner surface and a conical outer surface and an outer member 21 having an outer cylindrical surface and an inner conical surface. The tapering surfaces defined by means 26 and 21 cooperate with the wedge-shaped end of rubber sleeve H to make a fluid-tight seal when the end of the sleeve is secured to end plate 20 by bolts 25a. The outer surface of member 21 defines a groove having a rubber pack-off ring 28 arranged therein which insures a fluid-tight seal between the outer surface of member 21 and the inner surface of case II.

Secured to end plate II by suitable means. such as welding, are members 29 and 30 having a configuration identical with members 26 and 21, respectively. The outer surface of member 30 defines a groove for receiving a rubber pack-off 28 identical with that described with respect to member 21. When the end of the rubber sleeve I1 is brought into contact with end plate 2I by tightening bolts 25a, a fluid-tight joint is insured.

It is to be noted that the principal difference between end plate 2| and end plate 20 is that end plate 20 is secured to mandrel I4 by suitable means, such as welding, whereas end plate 2i is maintained in fixed position with respect to casing II and the member 29 secured to end plate 2| flts slidably on the exterior surface of mandrel I4.

It will be evident that the device of the present invention may be readily assembled and disassembled in construction and repair thereof. When the device is disassembled the most complex unit consists of mandrel I4, end member 20 and tapering members 26 and 21. Rubber sleeve I] may then be slipped over the mandrel I4 and an end secured to end plate 20 by means of bolts 25a. Outer casing II may then he slipped over the rubber sleeve until it abuts end plate 20 and it may then be secured in position by cap 22. End plate 2| with tapering members 29 and 30 may then be slipped over the end of mandrel It with bolts 25a passing through the end plate so that their threaded ends may be secured with nuts in the usual manner. The assembly may then be completed by attaching cap 23 to outer case II.

The device of the present invention is particularly adapted for attachment to a pipe or line carrying a stream of liquid having a pulsating pressure for the purpose of suppressing or dampening the vibration in the liquid. For use in such service it is desirable to secure a supply of compressed air to valve I8 and flll the chamber I8 with air at a pressure approximating the minimum pressure encountered in the pulsating stream. The device may then be fluidly connected by any conventional means, as by screw threads I6, to the pulsating stream. It will be understood that when compressed fluid is placed in cavity I8 without a corresponding pressure within mandrel I4, the inner surface of sleeve I1 is forced against the outer surface of mandrel I 4. Upon connecting the device with the source of pulsating pressure, the rubber sleeve will move through a cycle. Because of the compressible fluid maintained within cavity I8, the outer surface of sleeve I1 cannot be forced into direct physical contact with the inner surface of case II. The inner surface of rubber sleeve I! may or may not come into physical contact with the outer surface of mandrel I4 during that period in each cycle wherein the fluid pressure is a minimum within mandrel I4. It is preferred to adjust the pressures in cavity I8 and the pressure within the mandrel I4 during the cycle of pulsation so that the surfaces of rubber sleeve I I do not come into physical contact with the surface of mandrel I4. In other words, it is desirable for rubber sleeve I1 to be forced outwardly away from mandrel I4 during the high pressure portion of the cycle and toward the mandrel during the low pressure part of the cycle without coming into direct contact with the mandrel; the reason for not wishing to have direct contact between the rubber sleeve and the mandrel is to reduce the wear on the rubber sleeve. It will be understood that under some conditions of service it may be necessaryor desirable for the inner surface rubber sleeve I! to come in contact with mandrel I4 during a portion of each cycle.

It will be understood that the device of the present invention may be constructed of material of suitable constructural strength and dimensions adapted to the service intended. As a specific example, given by way of illustration and not intended to limit the invention in any way, it may be stated that suitable dimensions for a pulsation dampener adapted to dampen the pulsations in drilling fluid being passed from the outlet port of one pump to the inlet port of another pump when compounding mud pumps in a rotary drill-.

in rig may have an outer casing I I with an outside diameter 12% inches, a wall thickness of 1; inch and a length of 45 inches. The rubber sleeve II may have a normal outside diameter of '7 inches and a thickness of 1% inches while the mandrel I4 may have an outside diameter of approximately 4 inches.

While I have described the specific embodiment of the present invention it will be understood by a workman skilled in the art that various changes in the shape. size and proportion of the device may be made without departing from the scope of the invention.

Having fully described and illustrated the device of the present invention, what I desire to describe as new and useful and to secure by Letters Patent is:

1. In a pulsation dampener including a tubular mandrel having its central portion perforated, a flexible deformable sleeve having a wall arranged concentrically outside said mandrel, and a tubular casing arranged concentrically outside said sleeve, the improvement which comprises wedge-shaped end portions on each end of the wall of said sleeve with each wedgeshaped portion diminishing in thickness toward the distal end. a pair of annular end plates adapted to be arranged in said dampener at first and second ends, and spaced apart first and second wedge-shaped annular seating members abutting against said end plates enclosing a recess adapted to receive the wedge-shaped ends of said sleeve.

2. In a pulsation dampener including a tubular mandrel having its central portion perforated, a flexible deformable sleeve having a wall arranged concentrically outside said mandrel. and a tubular casing arranged concentrically outside said sleeve. the improvement which comprises wedge-shaped end portions on each end of the wall of said sleeve with each wedge-shaped portion diminishing in thickness toward the distal end, a pair of annular end plates adapted to be arranged in said dampener at first and second ends, spaced apart first and second wedgeshaped annular seating members abutting against said end plates enclosing a recess adapted to receive the wedge-shaped ends of said sleeve, and means to draw said wedge-shaped ends into said recesses.

3. In a pulsation dampener including a tubu-- rated, a flexible deformable sleeve having a wall arranged concentrically outside said mandrel,

and a tubular casing arranged concentrically outside said sleeve, the improvement which comprises wedge-shaped end portions on each end of the wall of said sleeve with each wedge-shaped portion diminishing in thickness towardthe distal end, a pair of annular end plates adapted to be arranged in said dampener at first and second ends, spaced apart first and second wedgeshaped annular seating members abutting against said end plates enclosing a recess adapted to receive the wedge-shaped ends of said sleeve, an annular supporting member embedded in the wedge-shaped ends of said sleeve. and

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 1 Date 2,278,688 Caminez Apr. 7, 1942 2,290,337 Knauth July 21, 1942 2,448,118 Pellettere Aug. 31, 1948 

